This invention relates generally to an improved motor driven centrifugal pump. More particular, but not by way of limitation, this invention relates to an improved axial balancing system for such pumps.
Various schemes have been proposed in the past for utilizing the fluid being pumped to balance the axial thrust developed by the centrifugal pump. One of such schemes is disclosed in U.S. Pat. No. 4,065,231 issued to David P. Litzenberg on Dec. 27, 1977. While the system described in that patent operates generally satisfactory, it has been observed that pumping occurs adjacent the balancing ports during operation of the pump, impending fluid flow through the ports and thereby creating a net axial force on the motor rotor and shaft toward the pump rotor.
Accordingly, an object of this invention is to provide an improved axial balancing system that functions to provide automatic and effective axial balancing of the forces generated by the pump rotor during operation.